The present invention relates to a method of manufacturing a Schottky barrier semiconductor device, and more particularly, to an improvement for minimizing variations in the barrier height .phi.B which would occur by heat treatment or use of the semiconductor device for a long period of time.
It is known that a barrier height .phi.B predominantly determines the properties of a Schottky barrier formed by combination of a semiconductor region and a barrier electrode. It is also found that the barrier height .phi.B tends to vary after heat treatment which is carried out for stabilization after completion of the semiconductor device. Specifically, the characteristic of Schottky barriers indicates that the reverse current leakage is decreased with a high level of the barrier height .phi.B and with increase of voltage drop of forward direction. Adversely, the voltage drop of the forward direction is decreased with a low level of the barrier height .phi.B and with increase of the reverse current leakage. Accordingly, it is desired that the barrier height .phi.B is adjustable in response to required electric properties.
However, the barrier height .phi.B of the Schottky barrier is predominantly determined depending on kind of a used barrier metal. Also, the barrier height .phi.B may tend to vary by heat treatment, and therefore it is difficult to stably control the barrier height .phi.B in a wide range.
Accordingly, an object of the present invention is to provide a method of manufacturing a Schottky barrier semiconductor device whose barrier height .phi.B may stably be adjusted to a desired level in a wide range.